A for-sale sign for the owner of the Staples Center arena, the NHL's Los Angeles Kings, Major League Soccer's LA Galaxy and a stake in the LA Lakers would be a major shock to the city's sports, entertainment and business establishment at any time.

But when Denver-based Anschutz Co. said Tuesday that it was "commencing a process" to sell subsidiary Anschutz Entertainment Group, the announcement left especially big questions about AEG's central role in courting the NFL's return to Los Angeles with Farmers Field, a planned downtown stadium going through late-round approvals with the city.

Mayor Antonio Villaraigosa was not so shocked, saying he had long known about the possible sale even as he publicly pushed for the building of the stadium. He insisted it would not derail the city as it pulls closer to the return of the NFL since the 1994 departure of the Rams and Raiders.

Villaraigosa said both Denver billionaire Phillip Anschutz and AEG President Tim Leiweke have assured him the city's football future will remain the same.

"I have worked with both Phil Anschutz and Tim Leiweke for years to bring a football team to Los Angeles. I speak to both of them on a regular basis, and I have known about this potential sale for some time," the mayor said in a statement Tuesday. "I have the commitment from both of them that this won't affect plans for an NFL team to return to Los Angeles in the near future and so will not affect my support for moving ahead with Farmers Field."

The stadium overcame a major hurdle last week when the city's planning commission unanimously recommended that the city council approve its environmental impact report. The council will take up the issue on Sept. 28.

If an agreement is reached, AEG and the city have said they would work on the puzzle's most important piece — persuading an NFL team to move — early next year.

Councilwoman Jan Perry, whose district includes the proposed stadium site next to the Staples Center, said she did not know about a pending sale but agreed that it wouldn't have adverse effects on courting a team.

"The city has done a good job of protecting the taxpayer's interest in negotiating an agreement," Perry told The Associated Press, "so whoever steps into the shoes of Mr. Anschutz will have the same obligations."

Perry said the move "arguably is very positive" because she suspected it could lead to an enthusiastic new partner anxious to get in on the city's NFL prospects.

It wasn't immediately clear how far along the company is in the sale process, or whether it has entertained any offers. The price for AEG could be well into the billions.

Anschutz Co. said in the statement that it has hired as financial advisers the Blackstone Group, which recently managed the sale of the Los Angeles Dodgers to a group that includes former Lakers star Magic Johnson.

"Given the success of the management team and employees in establishing AEG as one of the premier real estate development, live sports and entertainment platforms in the world," Anschutz president Cannon Y. Harvey said in a statement, "this is an appropriate time to transition AEG to a new qualified owner. This process represents a unique opportunity to maximize value for all concerned."

AEG's holdings also include the professional soccer team Los Angeles Galaxy, part-ownership of the NBA's Los Angeles Lakers, and major entertainment and real estate holdings in downtown Los Angeles. Outside of LA, AEG owns Major League Soccer's Houston Dynamo and arenas in Sweden, China and Australia.

The potential sale was first reported by the Wall Street Journal.

AEG transformed the city's landscape with the building of Staples Center and the addition of the LA Live entertainment complex, helping to revitalize a long-neglected downtown and bring energy and several championships to its sports teams.

Opened in 1999, the Staples Center is among the world's busiest arenas. It hosted six playoff games in four days for its main tenants — the NBA's Lakers and Clippers, and the NHL's Kings, who won their first Stanley Cup in June.